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Final presentation


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Final presentation

  3. 3. INTRODUCTION • The first modern air conditioning system was developed in 1902 by a young electrical engineer named Willis Havilland Carrier. • It was designed to solve a humidity problem at the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn, New York. • The cooling is typically done using a simple refrigeration cycle, but sometimes evaporation is used, commonly for comfort cooling in buildings and motor vehicles. • In construction, a complete system of heating, ventilation and air conditioning is referred to as "HVAC".
  4. 4. • Many of our homes , offices and commercial facilities would not be comfortable without control of the indoor environment. The "luxury label" attached to air conditioning made practicality our live healthier and more productive. • AutoCAD MEP is the AutoCAD software for mechanical, electrical, and plumbing designers and drafters. Creation and coordination of constructional documents is more efficient with AutoCAD MEP’s more intuitive systems drawing and design tools. • With AutoCAD MEP we are able to make changes much faster, thus help minimizing the financial impact, and make those changes in almost real time.
  5. 5. PROJECT GOAL • This project aims at studying the working phenomenon of Various AirConditioners and Designing an air-conditioning system in an economical way using AutoCAD MEP. • The goal of an HVAC system is to provide an energy efficient, cost effective, healthy and comfortable indoor environment with acceptable indoor air quality.
  6. 6. WHAT IS AIR CONDITIONING? • The air conditioning is the branch of engineering science deals with the study of conditioning of air, means supplying and maintaining desirable internal atmospheric conditions for human comfort, irrespective of external conditions. • Heating ventilating and air-conditioning HVAC is one of the building mechanical services that include plumbing, fire protection, and escalators. Air-conditioning refers to any form of cooling, heating, ventilation or disinfection that modifies condition of air. • Air conditioning (aircon or AC) is the process of altering the properties of air (temperature and humidity) to more favourable conditions. The acronym HVAC&R stands for heating, ventilating, air-conditioning, and refrigerating. The combination of these processes is equivalent to the functions performed by air-conditioning.
  7. 7. EQUIPMENTS USED IN AC SYSTEM • Circulation fan – to move air to and from the room • AC unit – For Cooling, Heating, Humidifying and Dehumidifying process • Supply duct – Directs conditioned air from the circulating fan to space • Supply outlets – Are grills which distribute the conditioned air evenly in the required space • Return outlets – Are the openings in the room surface which allow the room air to enter the return duct • Filters – For filtering dirt, dust and impurities
  8. 8. CASSIFICATION OF AC SYSTEM ACCORDING TO PURPOSE 1. Comfort Air Conditioning System 2. Industrial Air Conditioning System ACCORDING TO SEASON OF THE YEAR 1.Winter Air Conditioning System 2.Summer Air Conditioning System 3.Year Round Air Conditioning System ACCORDING TO ARRANGEMENT OF EQUIPMENT 1.Unitary Air Conditioning System 2.Central Air Conditioning System
  14. 14. WORKING PRINCIPLE • It is based on vapor compression refrigeration cycle. It includes four devices, 1.Evaporator 2.Comprssor 3.Condenser 4.Expansion valve. • When hot air flows over the cold, low pressure evaporator coils, the refrigerant inside absorbs heat as it changes from a liquid to a gaseous state • To keep cooling efficiently, the air conditioner has to convert the refrigerant gas back to a liquid again. • To do that, a compressor puts the gas under high pressure, a process that creates unwanted heat. • All the extra heat created by compressing the gas is then evacuated to the outdoors with the help of a second set of coils called condenser coils, and a second fan.
  16. 16. • As the gas cools, it changes back to a liquid, and the process starts all over again. • Thinking it as an endless, elegant cycle: liquid refrigerant, phase conversion to a gas/ heat absorption, compression and phase transition back to a liquid again.
  17. 17. Cooling-tower AC Units • Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. • This technology is used in HVAC systems for cooling buildings. • Cooling towers vary in size from small units to very large hyperboloid structures that can be up to 200 metres tall and 100 metres in diameter, or rectangular structures that can be up to 40 metres tall and 80 metres long. • Colling towers are classified into 2 types according to their use , such as 1.HVAC cooling tower and 2.Industrial cooling tower.
  18. 18. WORKING
  19. 19. The Objective of Air Conditioning System Design • The objective of an air conditioning system design is to achieve a highly quality system that functions effectively and is energy-efficient and costeffective. • The following are essential for a system to function effectively: 1. All design criteria are fulfilled, and the requirements of the owner and the user are satisfied. 2. A good indoor air quality is provided. 3. The system is reliable and has adequate fire protection level (e.g. smoke management).
  20. 20. DESIGN WORKFLOW OF HVAC SYSTEM • The design procedure of an Air Conditioning system includes the following steps : 1. Specifying the HVAC Parameters 2. Starting a Project 3. Linking System File to the Architectural Plan 4. Specifying Spaces and Zones 5. Calculating Loads
  21. 21. • Specifying the HVAC Parameters In this step, you need to specify all the basic parameters required to create an HVAC system. Some of the parameters are duct size, duct rise and drop, flow rate, cut length, and so on. On the basis of these parameters, the hierarchy of drawings in project will be decided. • Starting a Project In this step, you need to create a project file to link the drawings of a system to each other. For example, the drawings related to HVAC system will be interlinked and will be in the same project. As a result, you can easily manipulate the parameters of the system.
  22. 22. • Linking System File to the Architectural Plan To create an HVAC system, you need to have an architectural plan. In this step, you will link the HVAC system file to the architectural plan file using the Project Navigator. After the completion of this step, you can reroute the HVAC lines according to the architectural plan. • Specifying Spaces and Zones In this step, you need to create spaces and zones using the tools available in AutoCAD MEP. These spaces are used for exporting the building information related to the heating and cooling loads. The spaces are further divided into zones which represent the actual heating and cooling loads. • Calculating Loads In this step, you need to calculate the heating and cooling loads for the building. These calculations are performed by using the analysis tools available in AutoCAD MEP.
  23. 23. DESIGN METHODOLOGY • According to ASHRAE (American Society of Heating, Refrigerating and Air- Conditioning Engineers), AutoCAD MEP software & building information modeling (BIM) software, is used to design a central air conditioning system. Building engineering data have to be exported from architectural plans, using gbXML format, to Load soft 6.0 software for cooling load analysis. Then the total cooling load is to be calculated. • The calculated cooling load was imported to the AutoCAD MEP software which is used to design a central air conditioning system.
  24. 24. AutoCAD MEP Software • AutoCAD MEP is the AutoCAD software for mechanical, electrical, and plumbing designers and drafters. • In AutoCAD MEP software, it is possible to test design considerations in the virtual building model before anything, literally, gets set in concrete which is expensive to fix in the field. • AutoCAD MEP also assessing our vision and enhance our efficiency because of its purpose-built software for MEP designers and drafters.
  25. 25. FEATUTRS OF AutoCAD MEP • One of the major benefits of AutoCAD MEP is the improved coordination with the architectural and structural designs (mechanical, electrical, plumping). • Better Design Accuracy , • Coordinate Design Information , • Collaborate More Effectively , • Single/Double-Line Design and • AutoCAD MEP enable us to make zones boundaries
  26. 26. DESIGN OF CENTRAL AIR CONDITIOING SYSTEM Central air conditioning systems basically consist of three major parts 1. An air system or air handling unit (AHU), air distribution system (air ducts) and terminals(resisters and diffusers). 2. Water system – chilled water system, hot water system, condenser water system. 3. Central plant – refrigeration (chiller) plant, boiler plant. Central air conditioners circulate cool air through a system of supply and return ducts. Supply ducts and registers carry cooled air from the air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers
  27. 27. AIR HANDLING UNIT(AHU) We can arrange AHU separately to each floor or to the whole buildings.
  28. 28. AIR DISTRIBUTION SYSTEM Air Supply Ducts & Air Return Ducts • The size of ducts can be decreased by increasing the air velocity. Hence it is more common to use large ducts and the resultant low velocity air flow because high velocity air flow requires more fan power to generate and is much noisier. • Ducts are either round, rectangular, flat oval or square in cross-section. Round ducts are preferable for high velocity system and rectangular ducts are very popular for the typical low velocity system. • Aspect Ratio • Duct material
  29. 29. (Various types of supply and return ducts)
  30. 30. 2.Terminal Devices Terminal devices presents at the end of supply ducts. The supply air enters into the room through either a grille, resister or diffuser. • Grilles & Resisters A supply grille has adjustable vanes for controlling the direction of air entering the room. A resister is a grille that also has a damper behind it, so that the amount as well as the direction of air entering can be controlled. They should be located where occupants will not block them. • Diffusers Diffusers are used to mix the supply air with the room air rapidly. They can be round, rectangular or linear.
  31. 31. COOLING LOAD • The total heat required to be removed from the space in order to bring it at the desired temperature by the air conditioning is known as Cooling Load. The purpose of a load estimation is to determine the size of the air conditioning. • Sensible Heat Gain • When there is a direct addition of heat to the enclosed space, a gain in the sensible heat is said to occur. This sensible heat is to be removed during the process of summer air conditioning. • Latent Heat Gain • When there is an addition of water vapour to the air of enclosed space, a gain in latent heat is said to occur. This latent heat is to be removed during the process of summer air conditioning.
  32. 32. Sensible Heat Gain through Building by conduction
  33. 33. Heat Gain due to Infiltration Heat gain due to Ventilation • The ventilation is provided to the air conditioned space in order to minimise odour, concentration of smoke, carbon dioxide and other undesirable gas so that freshness of air should be maintained.
  34. 34. DESIGN SOLUTION • For analysis purpose we considered the installation of central air conditioning unit in our college conference hall. • No. of person=250, td2=22ᵒc,Ф2=60%, td1=40ᵒc,tw1=27ᵒc . • The floor diagram for the given air conditioning system is shown in figure. The various points on the psychrometric chart, are shown in figure are marked as discussed below. • First of all, mark the outside condition of air that is 40ᵒc DBT and 27ᵒcWBT on the psychrometric chart as point 1, as shown in figure. Now mark the inside condition of air in the room i.e. 22ᵒc dbt and 60% relative humidity as point 2. Locate point A by drawing vertical and horizontal lines through point 1 and 2 respectively.
  35. 35. Psychrometric Chart
  36. 36. CONCLUSION • In this project, AutoCAD MEP program, building information modeling (BIM) software, is used to design a central air conditioning system. Building engineering data have been exported from architectural plans, using gbXML format, to Loadsoft 6.0 software for cooling load analysis. The software obtained a total cooling load of 53.22 KW. • The calculated cooling load was imported to the AutoCAD software which is used to design a central air conditioning system. The software analyzed the imported data and used it for duct sizing and equipment selection.
  37. 37. REFERENCES • Air conditioning course notes, university of Khartoum. • Walter T.Grondzic, Air conditioning system design manual, second edition. • An Introduction to building information modeling, 2009. • Autodesk Company, autocad mep brochure, 2009. • Autodesk Company, AutoCAD MEP 2010 user’s guide, March 2009.